Bone Cancer

Bone cancer can be distinguished into primary and secondary bone cancer. When cancer spreads within the cells of the bone, it is classified as Primary Bone Cancer.  Examples of primary bone cancer include Osteosarcoma, Ewing Sarcoma, Malignant Fibrous Histiocytoma and Chondrosarcoma.

In cases where cancer which originated from another part of the body, has spread to the bone, it gets classified as Secondary Bone Cancer.

The most common symptom of cancerous tumours in bone are pain, which gradually increases over time with the creation of bone lesions.

Other symptoms include:

• Fatigue
• Fever
• Anaemia
• Bone fractures

Many patients will not experience any symptoms making the prognosis difficult. The only giveaway would be a painless mass which could confirm bone cancer. Some bone tumours may weaken the structure of the bone causing pathologic fractures.

Although bone cancer does not have a clearly defined cause, researchers have identified several factors that increase the likelihood of developing these tumours.

Myeloma, a type of white blood cell which produces antibodies, has a probability of multiplying unusually or releases too much protein (immunoglobulin) into the bones and blood, giving rise to bone cancer.

Osteosarcoma occurs more frequently in people who have had high-dose external radiation therapy or treatment with certain anticancer drugs. Studies indicate that children are more susceptible to osteosarcoma.

A small number of bone cancers are due to heredity. For example, children who have had hereditary retinoblastoma (an uncommon cancer of the eye inherited by a faulty gene) are at a higher risk of developing osteosarcoma.

It is also observed individuals who have hereditary defects of bones or metal implant to correct fractures, are more likely to develop osteosarcoma.

The following groups have a higher chance of developing bone cancer:

• Children & Adults below the age of 20 are more likely to get bone cancer. Bone cancer below 20 is largely unknown. In some cases it is attributed to hereditary factors.
• Patients with a history of radiation therapy
• People with a history of Paget's disease ( which interferes with the bone’s natural recycling process)
• People with a close relative (parent or sibling) who has/had bone cancer.
• People with Li-Fraumeni syndrome (a mutation of the tumour suppressing gene TP53)
• Babies born with an umbilical hernia

The doctor may order a blood test to identify the cause of the cancer. The patient will then be referred to a bone specialist (orthopaedic surgeon) to examine the bone tumour. The following diagnostic tests may be ordered:

• Bone scan: a liquid which contains radioactive material is injected into a vein. This material collects in the bone, especially in abnormal areas, and is detected by a scanner. The image is captured on a special film.
• Computerized Tomography (CT): the CT scanner uses digital geometry processing to generate a 3-dimensional (3-D) image of the inside of an object. The 3-D image is made up of many 2-dimensional (2-D) X-ray images, taken around a single axis of rotation - in other words, many pictures of the same area are taken from different angles and then placed together to produce a 3-D image. It is a painless procedure. CT scans are commonly used to see whether the bone cancer has spread and where it has spread to.
• Magnetic Resonance Imaging (MRI): the device uses a magnetic field and radio waves to create detailed images of the body. Most MRI machines look like a long tube, with a large magnet present in the circular area. When beginning the process of taking an MRI, the patient is laid down on a table. Depending on where the MRI needs to be taken, the technician slides a coil to the specific area which is being imaged. The coil is the part of the machine that receives the MR signal, thereby completing the imaging process.
• Positron emission tomography (PET): A PET scan uses radiation or nuclear medicine imaging, to produce 3-dimensional, colour images of the functional processes within the human body. The machine detects pairs of gamma rays which are emitted indirectly by a tracer (positron-emitting radionuclide) which is placed in the body on a biologically active molecule. The images are reconstructed by computer analysis.
• X-rays: This type of scan can detect damage caused by the cancer. It may also detect new bone cells that have started to form around the tumour. An x-ray does not provide enough data for a definitive diagnosis, but can help the surgeon decide the prognosis of the disease and prescribe necessary treatment.
• Bone biopsy: A sample of bone tissue is extracted and examined for cancer cells. This is the most reliable way to diagnose bone cancer. The standard process involves inserting a long, thin needle into the bone and removing a sample, while an open biopsy involves making an incision in the target bone area and surgically removing a sample of the tissue.

The options on treatment for bone cancer depends on several factors, such as what type of bone cancer it is, where it is located, how aggressive it is, and whether it is localized or spread. There are typically 4 stages of bone cancer which have various treatment options. If the tumour in the bone is of low grade, it is called as Stage 1 Bone Cancer. In case the cancer in the bone is of high-grade, then it is classified as Stage 2 Bone Cancer. A Metastatic bone cancer which has spread to other parts of the bone then it is called Stage 3 Bone Cancer. Advanced cases where it has spread to other parts of body gets classified as called Stage 4 Bone Cancer. Some of the latest bone cancer treatment options that available are:

• Surgery
• Radiotherapy (Radiation Therapy)
• Chemotherapy

Surgery – in this form of bone cancer treatment, the aim is to remove the tumour completely along with some of the bone tissue that surrounds it. If some of the cancer is left behind after surgically removing the tumour, it may continue to grow and eventually spread. Limb sparing surgery, also known as limb salvage surgery means that surgical intervention occurs without having to amputate the limb. During the leg or arm treatment, the surgeon may take some bone from another part of the body to replace lost bone (bone graft), or an artificial bone may be put in. In some cases, however, amputation of a limb may be necessary during treatment.

Radiation Therapy – it is also known as radiotherapy, radiation oncology and XRT. Approximately 40% of patients of all types of cancer undergo some kind of radiotherapy. It involves the use of beams of high-energy X-rays or radiation particles to destroy cancer cells for a certain duration based on treatment. Radiotherapy works by damaging the DNA inside the tumour cells, destroying their ability to reproduce. This type of treatment is recommended for Metastatic bone cancer treatment. Radiotherapy can be used for different reasons:

• To suppress the tumour
• To alleviate bone cancer symptoms
• Neo-adjuvant radiotherapy (before surgery), a form of radiotherapy to shrink the tumour and allowing it to be removed surgically.
• Adjuvant radiotherapy to eliminate the cancer cells that remained after the surgery.
• Combination therapy (radiotherapy combined with another type of therapy) - in some cases, radiation is combined with chemotherapy.

Given the benefits of radiation therapy, the patient must be wary of the side effects during the treatment which ranges from Fatigue, Loss of Appetite & changes in the skin area where it treated. Common skin changes include redness, hair loss, blistering & peeling. There are also instances of low blood counts, nausea, vomiting and diarrhoea. In special cases where the pain aggravates, it would be advisable to talk to your treatment doctor.

Chemotherapy is the use of chemicals (medication) to treat disease, specifically for the destruction of cancer cells. During the treatment, cytotoxic medication prevents cancer cells from dividing and growing. In general, chemotherapy has 5 possible goals:

• Total remission - to treat the cancer
• Delay/Prevent recurrence – to prevent the recurrence of cancer, especially after surgery.
• Slow down cancer progression - used mainly when the cancer is in its advanced stages and a positive outcome is unlikely, where it can slow down the rate of growth of cancer.
• To relieve symptoms – especially for patients with advanced cancer.